Bleachability test for colored fabrics

ABSTRACT

A method for rapidly and simply determining the susceptibility of a fabric to color change in a wash solution including bleach, comprising the steps of preparing a test solution having an available chlorine concentration of within the approximate range of 4,000 to 10,000 parts per million (ppm), saturating a small area of the fabric with the solution, drying the fabric, and comparing the dried fabric with a similar untreated fabric to determine if there has been a color change.

OTHER PUBLICATIONS National Institute of Dry Cleaning, PracticalOperating Tips, Bulletin P-8, Oct. I953.

United States Patent [191 [11] Woodward Dec. 10, 1974 BLEACHABILITY TESTFOR COLORED National Institute of Dry Cleaning, Practical Operat-FABRICS ing Tips, Bulletin P-23, April i957.

[75] Inventor: Eats;- K. Woodward, San Rafael, Primary Examiner JosephScovmnek Assistant Examiner-Barry I. Hollander [73] Assignee: The CloroxCompany, Oakland, Attorney, Agent, or Firm-Phillips, Moore,

Calif- Weissenberger, Lempio & Strabala 22 F1 d: 26 1972 1 1e June 57ABSTRACT [21] Appl' 266049 A method for rapidly and simply determiningthe susceptibility of a fabric to color change in a wash solu- 52 US.Cl. 8/137, 23/230 R, 8/108 tipn including bleach, comprising the stepsof p p 51 1 3 H 0 3 0 0 1 3 1 01 33 3 ing a test solution having anavailable chlorine con- 58] Field of Search 23/230 R; 8/19, 101, 108,centration of within the approximate range of 4,000 to 8/137 10,000parts per million (ppm), saturating a small area of the fabric with thesolution, drying the fabric, [56] Ref Ci d and comparing the driedfabric with a similar untreated fabric to determine if there has been acolor change.

6 Claims, 1 Drawing Figure 3 80 Q LLI n: 0.

g 88 s 8 Q 0 N we 8 AVAILABLE CHLORINE p. p. m.

1 BLEACHABILITY TEST FOR COLORED FABRICS The present invention relatesto a method for predicting or determining if a fabric will remainsubstantially colorfast in a wash solution including bleach. Bleach haslong been used in wash solutions in combination with detergents formaximum stain removal, soil removal and disinfection, particularly inthe laundering of white fabrics. The same advantages may be achieved inthe laundering of colored fabrics by using bleach. With the fiber anddye combinations presently available for various types of coloredfabrics, it has been found that most of them may now also be subject towash solutions including bleach without experiencing a color change.

Certain fabrics, however, still remain susceptible to color change whenimmersed in a wash solution including bleach. Most fabrics or garmentsare not marked to indicate whether or not they will remain colorfast ifbleach is used in the wash solution. Accordingly, it has heretofore beennecessary to conduct relatively laborious and time consuming individualtests on garments and fabrics to determine if they will remain colorfastafter being washed one or more times with bleach. For example, one testhas been to merely duplicate the wash conditions on a limited portion ofthe fabric. In this test, the fabric must remain in the test solutionfor a substantial period of time. Tests of this type are both awkwardand unreliable since it isnot possible to duplicate wash cycleconditions to which the fabric may be subjected.

In overcoming this problem, the present invention has been found toprovide a simple and reliable method of predicting or determiningwhether a fabric will re main colorfast upon being subjected tooxidation conditions in wash solutions including a bleach. The inventionis based upon the unexpected discovery that susceptibility of the fabricto color change may be predicted by subjecting it for a short period oftime to a solution having a substantially increased available chlorineconcentration within a selected range.

In a typical wash solution, including both detergent and a hypochlorite,the available chlorine concentration may be in the range of up toapproximately 200 ppm. By the present invention, it has been found'thatthe color fastness of a fabric subjected to such a wash solution may beaccurately predicted by subjecting a small area of the fabric to a testsolution having an available chlorine content within the approximaterange of 4,000 to 10,000 ppm. In other words, the color fastness offabrics may be rapidly and accurately determined prior to subjectingthem to a wash solution including bleach by spot testing the fabric witha test solution having an available chlorine concentration very muchgreater than the normal available chlorine concentration in the washsolution. A wide variety of fabrics was tested with solutions havingwidely varying concentrations of'available chlorine with the abovenotedrange being particularly and unexpectedly effective for predicting thecolor fastness of various fabrics.

The most common type of color change which may occur under theseconditions, of course, is the simple fading of colors where the dyes areunduly affected by the bleach. However, other types of undesirable colorchange may also be predicted by the present invention. For example,while most of the modern parmanent press fabrics can be safely subjectedto solutions including bleach, certain of them have resin finishes whichmay tend to yellow under such condition. The present test method hasalso been found effective for use in determining the tendency of suchfabrics to yellow.

The method of detennining the accuracy of the present test in predictingcolor fastness of various fabrics is discussed in greater detail below.In general, test solutions of different available chlorineconcentrations were applied to different portions of the fabrics.Similar fabrics were then subjected to one or more wash cycles includingbleach, these fabrics then being correlated for color fastness with thesimilar spot tested fabrics. It was thus discovered that, through theuse of a test solution having an available chlorine concentration withinselected limits, the color fastness of the various fabrics could bepredicted with a high degree of accuracy.

The accompanying drawing graphically illustrates the effectiveness ofthe present invention in predicting color fastness of fabrics. In thedrawing, the percent predictability of color change is plotted versusthe concentration of available chlorine in a test solution applied tothe fabric. Referring to the drawing, it may be noted that the percentpredictability or the effectiveness of the present method isparticularly high when the concentration of available chlorine ismaintained within the selected limits taught by the present invention.

In determining the accuracy of the present method, a variety of fabricsand many different classes of dyestuff were tested. Forexample, theevaluated fabrics included both natural and man-made fibers, as well asfiber blends. Specific fibers included in the tests were cotton, linen,rayon, cellulose acetate (secondary), cellulose triacetate,.polyester,nylon, acrylic, modacrylic and polypropylene. Various dyestuffs includedin the test were direct, disperse, vat, sulfur, azoic, acid, acidpremetalized and cationic (basic) dyes. As is commonly known within theart, certain of these dyes are specifically adapted for usewith certainof the fabrics listed above. For purposes of the present invention, thefibers and dyestuffs listed above are intended only to illustrate thatthe present invention has been found to be effective for a large crosssection of fibers and associated dyes presently available.

Tests to determine the predictability of the present method were carriedout on different fabric and dye combinations. Each of the sample fabricswas cut into at least two portions. One portion of each fabric wassubjected to a typical wash solution including both detergent andbleach. Washing of these fabrics was carried out in an automatic washingmachine having an operating cycle of: fill, agitate (wash), drain, spin,fill, rinse, drain and spin. The wash water used in these tests wasapproximately 1 15F, which is believed to most accurately correlate withtypical temperatures employed within such machines. However, it is notedthat home laundries may commonly employ water having a temperature of upto F or a substantially lower temperature, for example in cold waterwashing and the tests described herein for the present invention arebelieved to be representative. The wash solution to which the variousfabrics were subjected was prepared by adding one-fifth cup of a typicalcommercial grade detergent (such as sodium dodecylbenzene sulfonate) andone cup of a bleach (such as an aqueous solution of approximately 5.25percent sodium hypochlorite) to approximately 16 gallons of water.

The other portion of each fiber sample was treated in differentlocations with drops of test solution having varying concentrations ofavailable chlorine. The test solutions were prepared by adding suitablequantities of the above noted hypochlorite bleach (commerciallyavailable for example, under the trade name Clorox) to the water. Aconcentration of approximately 10,000 ppm available chlorine may beobtained by mixing one part of the above noted commercial liquid bleachwith approximately four parts of water. It is necessary to assure thateach drop penetrates the fabric. On certain water repellent fabrics, thedrop of test solution may tend to bead up, but it was found that thetest solution could be readily induced to penetrate the fabric in eachinstance, for example, by working the solution into the fabric with aglass or polyethylene rod. The test solution was applied to the fabricat room temperature, generally within the range of 60-90F, and allowedto stand for approximately 1 minute.

The spots on the fabric treated with the test solution I were thenblotted dry with paper towels and compared with the other fabric samplesfor color change. The determination of color difference between thesimilar types of fabric could be carried out by various mechanical meansor standard test methods, such as the well known Gray Scale for example.However, since it was anticipated that the test would normally beconducted where such test apparatus was not available, the colorcomparison was made by visually examining the fabrics to determine if acolor difference could be observed. As shown on the graph, it was foundthat spot testing the various fabrics with a test solution having anavailable chlorine'concentration of about 5,000 ppm correctly indicatedcolor fastness for 98 out of the 105 different fabrics tested,equivalent to a 93.3 percent predictability. With a test solution havingan available chlorine concentration of 10,000 ppm, 97 of the 105 fabricswere correctly predicted for a predictability percentage of 92.4percent. By comparison, when the test solution had an available chlorineconcentration of 20,000 ppm, color fastness for only 85 of the 105fabric samples was correctly indicated for a predictability percentageof 81.0 percent. The present predictability similarly dropped off at avery rapid rate when the concentration of available chlorine wassubstantially below 4,000 ppm. Accordingly. color fastness of variousfabrics may best be indicated by applying a test solution having anavailable chlorine concentration within the approximate range of 4,000to 10,000 ppm in the manner described above.

What is claimed is:

1. In a method of washing colored fabrics by subjecting them tooxidation conditions in an aqueous wash solution including detergent andbleach, the wash solution having an available chlorine concentration ofup to approximately 200 ppm and a temperature of up to approximately F,the steps comprising:

preparing a test solution having an available chlorine concentration ofabove 4000 and below 10,000

pp treating a small area of the fabric with the test solution, bysaturating the small area of the fabric with the test solution, thendrying the fabric,

comparing the treated fabric when substantially dry with similaruntreated fabric for color differences, and excluding only those fabricsexhibiting said color difference from said wash solution and subjectingthe remaining fabrics to said wash solution in a subsequent washingstep.

2. The method of claim 1 wherein the test solution comprises ahypochlorite.

3. The method of claim 1 wherein the test solution comprises sodiumhypochlorite.

4. The method of claim 1 wherein the step of treating the fabriccomprises saturating the fabric with the test solution for approximately1 minute and then blotting the saturated fabric so that it issubstantially dry prior to the comparison step.

5. The method of claim 4 wherein the test solution comprises ahypochlorite.

6. The method of claim 1 wherein the step of treating the fabriccomprises saturating the fabric with a small portion of the testsolution at a temperature of approximately 60-90F for approximately 1minute and then substantially drying the saturated fabric prior tocomparing it with untreated fabric for color change.

1. IN A METHOD FOR WASHING COLORED FABRICS BY SUBJECTING THEM TOOXIDATION CONDITIONS IN AN AQUEOUS WASH SOLUTION INCLUDING DETERGENT ANDBLEACH, THE WASH SOLUTION HAVING AN AVAILABLE CHLORINE CONCENTRATION OFUP TO APPROXIMATELY 200 PPM AND A TEMPERATURE OF UP TO APPROXIMATELY150*F, THE STEPS COMPRISING: PREPARING A TEST SOLUTION HAVING ANAVAILABLE CHLORINE CONCENTRATION OF ABOVE 4000 AND BELOW 10,000 PPMTREATING A SMALL AREA OF THE FABRIC WITH THE TEST SOLUTION, BYSATURATING THE SMALL AREA OF THE FABRIC WITH THE TEST SOLUTION, THENDRYING THE FABRIC, COMPARING THE TREATED FABRIC WHEN SUBSTANTIALLY DRYWITH SIMILAR UNTREATED FABRICS EXHIBITING SAID COLOR DIFFERENCE ING ONLYTHOSE FABRICS EXHIBITING SAID COLOR DIFFERENCE FROM SAIID WASH SOLUTIONAND SUBJECTING THE REMAINING FABRICS TO SAID WASH SOLUTON IN ASUBSEQUENT WASHING STEP.
 2. The method of claim 1 wherein the testsolution comprises a hypochlorite.
 3. The method of claim 1 wherein thetest solution comprises sodium hypochlorite.
 4. The method of claim 1wherein the step of treating the fabric comprises saturating the fabricwith the test solution for approximately 1 minute and then blotting thesaturated fabric so that it is substantially dry prior to the comparisonstep.
 5. The method of claim 4 wherein the test solution comprises ahypochlorite.
 6. The method of claim 1 wherein the step of treating thefabric comprises saturating the fabric with a small portion of the testsolution at a temperature of approximately 60*-90*F for approximately 1minute and then substantially drying the saturated fabric prior tocomparing it with untreated fabric for color change.